Wager games come in a variety of forms, including for example a mechanical slot machine. A mechanical slot machine may include one or more reels, each of which includes a fixed pattern of symbols distributed around the circumference of the reel. When a player places a wager (e.g., by placing a coin in the machine), the player is allowed to spin the reels. Each reel then comes to rest, typically with either one of the symbols, or a space in between symbols, in alignment with a pay line. A predefined winning symbol or a predefined combination of winning symbols that are aligned with the pay line can result in the player winning the game and receiving a payout. In one example, the machine may include three reels, and the pay line may be a horizontal line disposed across a centre of each of the three reels.
In another example of a wager game, a mechanical slot machine may present symbols in a matrix arrangement, with each symbol changing during a spin of the game according to the fixed pattern of symbols on the reels. For example, the machine may have five columns and three rows of symbols, for a total of fifteen symbols. Such machines often have multiple pay lines, each being defined by a collection of positions within the matrix. For example, the machine may have three pay lines, each corresponding to one row of the matrix.